Improving upconversion emission of NaYF4:Yb3+, Er3+ nanoparticles by coupling Au nanoparticles and photonic crystals: The detection enhancement of Rhodamine B

Abstract The upconversion (UC) nanoparticles (NPs) based sensor exhibits the potential application for the detection of dyes, heavy metal ions and DNA et al. However, the application of upconversion NPs based sensor was limited due to its low UC luminescence intensity. In the present work, the SiO 2 opal photonic crystals were prepared by the self-assembly technology. After infiltration of SiO 2 opal by the transparent chloroauric acid solution and the following sintering at the high temperature, the Au NPs/opal hybrids were prepared. The Au NPs/opal hybrids result in the enhancement of excited electric field, which can be served as the template of UC emission enhancement of NaYF 4 :Yb 3+ , Er 3+ NPs exited at the 980 nm. The corresponding maximum UC emission enhancement was about 17-fold. The detection of Rhodamine B was realized by monitoring the changing of green UC intensity of NaYF 4 :Yb 3+ , Er 3+ NPs. In comparison with pure NaYF 4 :Yb 3+ , Er 3+ NPs, the sensor sensitivity of NaYF 4 :Yb 3+ , Er 3+ NPs deposited on the Au NPs/opal hybrid was increased by about the 35-factors, which exhibits a low detection limit of 164 μM and a high sensitivity of 1.15 μM −1 . The present work demonstrated that this solid sensor exhibits potential applications in heavy metal ions and DNA et al.